Such sources already exist which essentially comprise a laser generator in association with an electro-acoustic deflector disposed at the outlet from the laser generator and controlled, for example, by a frequency source which delivers a control signal in the form of ultrasonic waves to the electro-acoustic deflector. Such sources are capable of deflecting the outlet beam by predetermined angles. However, it is known that laser generators are not perfectly monochromatic, ie. they deliver a beam that is composed of a plurality of beams of differing wavelengths, eg. red, blue, and green.
Further, it is well known that the angle through which deflectors such as the one mentioned above deflect beams of light depends on the wavelength of the light in addition to the control signal applied to the deflector.
Consequently, when such a deflector is disposed at the outlet from such a laser generator, it delivers a plurality of beams propagating in different directions. In other words, it acts somewhat like a variable angle prism.
It will thus be readily understood that, by virtue of the beam being decomposed, there are some applications for which such sources cannot be used because the decomposition of the beam detracts from the desired result.
At present such sources are in use in applications as varied as aeronautics, advertising, and civil engineering. In particular they are used to write words or pictures in light on screens of all kinds.
Thus, to properly trace such curves, it is essential to eliminate all wavelengths bar one to ensure that the curve is composed of one line only.
To eliminate the unwanted wavelengths, devices such as prisms or interference filters are used in various light sources.
It will be understood that eliminating the majority of these beams while leaving just one remaining beam has the undoubted effect of reducing the power available in the beam coming from the outlet of the deflector. This means that currently available sources cannot be used in all applications at high efficiency.
Preferred embodiments of the present invention provide a pointable light source including an emitter of light and capable of making use of all the emitted light with minimal power loss, thereby making the source useable in any application and at noticeably higher efficiency than light sources which are currently commercially available.